Anisakis simplex only provokes allergic symptoms when the worm parasitises the gastrointestinal tract

Abstract

We analysed patients with allergic or digestive symptoms after seafood ingestion in order to assess a correct diet in Anisakis simplex sensitised individuals. A total of 120 patients who suffered allergic and/or digestive symptoms after marine food ingestion were studied. We performed skin prick tests for A. simplex and seafood, total serum and specific serum immunoglobulin E to A. simplex in the acute stage and 1 month later. A gastroscopy was carried out to find larvae in those patients with persistent abdominal pain. A challenge with non-infective larvae was performed to assess a correct diet. Some 96 patients were sensitised to A. simplex. Gastroscopy was performed in 47 and we detected larvae in 24. We compared symptoms, skin tests, total and specific IgE and the latency of appearance of symptoms in patients positive for Anisakis larvae, patients without larvae at gastroscopy and patients without digestive symptoms. There was no difference among the groups. We challenged 22 patients with frozen A. simplex larvae. After allowing deep-frozen seafood in the diet for more than 2 years, no patient suffered a reaction. At this time, we allowed all our patients well-frozen seafood without any allergic reaction occurring. Allergic symptoms are the most frequent manifestation of A. simplex parasitism. We could not find any patient allergic to the thermostable proteins of parasite.

Diagnosing Human Anisakiasis: Recombinant Ani s 1 and Ani s 7 Allergens versus the UniCAP 100 Fluorescence Enzyme Immunoassay

“…In consequence, it appears more likely that the large number of positive results obtained with CAP FEIA is the result of the detection of IgE antibodies induced by other allergens that share common epitopes with Anisakis allergens, as previously reported (15,18,29). Differentiation of Anisakis infections from those induced by cross- reacting allergens is of great clinical relevance because the former can easily be prevented by avoiding eating raw or undercooked fish, even with very low levels of parasites (2,34).…”

“…Indeed, on the basis of previous reports (9,27), it could be argued that in addition to Anisakis infections, CAP FEIA detects IgE antibodies induced by free Anisakis allergens that are present in fish contaminated with this parasite and categorizes the patients as positive. However, this hypothesis appears unlikely, considering the negative results obtained in provocation test studies carried out on sensitized patients, using frozen (1,2,14), freeze-dried (32), or excretory-secretory (6) antigens, as well as in experiments conducted in a murine model of anaphylaxis (7). In consequence, it appears more likely that the large number of positive results obtained with CAP FEIA is the result of the detection of IgE antibodies induced by other allergens that share common epitopes with Anisakis allergens, as previously reported (15,18,29).…”

Anisakis simplex: from Obscure Infectious Worm to Inducer of Immune Hypersensitivity

“…In Western Europe, herring (Clupea arengus) is the main species involved (195,274,275), although cases with other species that were insufficiently cooked (microwaved, grilled, or shallow fried) have also been reported. In Spain, most cases have been related to the consumption of pickled anchovies (Engraulis encrasicholus) (10,69).…”

TheAnisakis simplexAni s 7 major allergen as an indicator of trueAnisakisinfections

“…Another characteristic of Anisakis-induced allergy is that either the ES allergens [12] or the allergens stored inside dead larvae [13][14][15] when administered to previously sensitized patients by the oral route. These results suggest that: (i) immunization against clinically relevant Anisakis allergens is only possible during the course of an active infection; and (ii) that these allergens are destroyed during the digestion process.…”